I have been trying to get an optimized structure of transition state confirmed with IRC but if says exceeding maximum corrector steps so is there any other way that I can rtack the starting material and product?
Thanks.
If you are encountering issues with the optimization of a transition state using the Intrinsic Reaction Coordinate (IRC) calculation and receiving an error message indicating that the maximum corrector steps are being exceeded, there are a few potential approaches you can try:
It's important to note that the specific details and solutions may vary depending on the software package you are using for your calculations. Providing more information about the software and the system you are working on can help in giving more tailored suggestions.
Madhusha Manna Peruma If the IRC (Intrinsic Reaction Coordinate) calculations are not working due to exceeding the maximum corrector steps, there are alternative methods you can use to track the starting material and product and confirm the transition state in Gaussian calculations. Here are a few options:
1. Nudging: Nudging is a technique where you manually perturb the optimized structure slightly along the reaction coordinate and then re-optimize it. By incrementally adjusting the geometry along the reaction path, you can explore the vicinity of the transition state. This can provide insights into the transition state and help confirm its correctness.
2. Potential Energy Surface (PES) Scanning: PES scanning involves systematically varying a set of coordinates that are relevant to the reaction pathway while keeping the others fixed. By scanning the potential energy surface, you can identify points along the reaction coordinate that correspond to the starting material, transition state, and product. This method can help you locate and validate the transition state.
3. Transition State Guess: If you have some prior knowledge or intuition about the reaction, you can make an educated guess of the transition state geometry based on your understanding of the reaction mechanism. You can then use this guess as an initial geometry for a new optimization. This approach requires some expertise and familiarity with the reaction you are studying.
4. Reaction Coordinate Calculations: Instead of IRC calculations, you can perform reaction coordinate calculations. In this method, you define a specific reaction coordinate (e.g., a bond distance) and optimize the structure while keeping the reaction coordinate fixed. By varying the value of the reaction coordinate and optimizing the geometry at each point, you can identify the transition state along the reaction pathway.
5. Consult Literature: If you are working on a well-studied reaction, it may be beneficial to consult the literature to see if there are any established transition state structures or alternative methods suggested by other researchers. This can provide valuable insights and guidance for your own calculations.
It's important to note that the choice of method depends on the specific reaction you are studying and the available resources. It is recommended to consult with experienced researchers or experts in the field to discuss the best approach for your particular case.